   ;; export all hashtags
   (letfn [(extract-hashtags [{{:keys [hashtags]} :entities}]
             (pmap :text hashtags))]
-    (let [tweets (mc/find-maps @db "tweets" {:created_at {$gt (t/date-time 2014 7 1)
-                                                          $lt (t/date-time 2014 10 1)}
+    (let [tweets (mc/find-maps @db "tweets" {:created_at {$gt (t/date-time 2014 8 1)
+                                                          $lt (t/date-time 2014 9 1)}
                                              :entities.hashtags {$ne []}})]
       (time
        (doall

  ;; export users
  (time
   (letfn [(user-exists? [{{:keys [id]} :user}] (mc/find-one @db "users" {:id id}))]
     (let [tweets (mc/find-maps @db "tweets" {:created_at {$gt (t/date-time 2014 9 1)
                                                           $lt (t/date-time 2014 10 1)}})]
       (doall
        (pmap #(when-not (user-exists? %) (store-user %)) tweets)))))





  ;; export tmp urls
  (letfn [(x-url [url]
            (let [expanded-url (-> url :url expand-url :url)]
